Hypermethylation of Sox17 gene is useful as a molecular diagnostic application in early gastric cancer.

Although minimal invasive treatment is widely accepted in the early stages of gastric cancer (GCa), we still do not have any appropriate risk markers to detect residual neoplasia and the potential for recurrence. We previously reported that aberrant DNA methylation is an early and frequent process in gastric carcinogenesis and could be useful for the detection of gastric neoplasia. Our goal is to find and identify some candidate genes, using genome-wide DNA methylation analysis, as a treatment marker for early gastric cancer (EGC). We performed methylated CpG island amplification microarray analysis using 12 gastric washes (six each of pre- and post-endoscopic treatment in each of the same patients). We finally focused on Sox17 gene. We examined the DNA methylation status of Sox17 in a validation set consisting of 128 wash samples (pre, 64; post, 64) at EGC. We next carried out functional studies to identify Sox17. Sox17 showed significant differential methylation between pre- and post-treatments in EGC patients (Sox17, p < 0.0001). Moreover, treating GCa cells that lacked Sox17 expression with a methyltransferase inhibitor, 5-aza-2'-deoxycytidine, restored the gene's expression. Additionally, the introduction of exogenous Sox17 into silenced cells suppressed colony formation. Gastric wash-based DNA methylation analysis could be useful for early detection of recurrence following endoscopic resection in EGC patients. Our data suggest that the silencing of Sox17 occurs frequently in EGC and may play a key role in the development and progression of the disease.

Gastric wash-based molecular testing for antibiotic resistance in Helicobacter pylori.

BACKGROUND: A number of noninvasive tests have been developed to establish the presence of Helicobacter pylori infection. However, thus far these tests have only been capable of detecting its presence. An increasing number of antibiotic-resistant H. pylori infections have been reported and they are known to be correlated with 23S rRNA single nucleotide polymorphisms (SNPs). We hypothesized that genomic analysis of H. pylori recovered from gastric washes could not only be less invasive, but also useful as a screening test and for assessing the outcome of eradication therapy. METHODS: Biopsy specimens and gastric washes were collected from 100 patients during endoscopic examination. Then we analyzed 23S rRNA, ureA, and cagA genes using PCR and high-throughput pyrosequencing analysis. RESULTS: Forty-five percent (44/97) of patients tested positive for ureA and 42.3% (41/97) tested positive by a rapid urease test. One hundred percent (35/35) of patients who tested positive by both methods were observed to have the cagA gene. Among these 35 patients, 23S rRNA SNPs were present in 34.3% (12/35). CONCLUSIONS: Gastric wash-based PCR and a pyrosequencing assay were used to rapidly detect and estimate the number of 23S rRNA SNPs in clinical isolates of H. pylori. Not only is this a less invasive technique, but it can also diagnose drug resistance.

Past, present, and future of the Korea-Japan Joint Symposium on Gastrointestinal Endoscopy.

We herein discuss the history, the present situation, and the future prospects of Korean Society of Gastrointestinal Endoscopy (KSGE) and Japan Gastroenterological Endoscopy Society (JGES). Through the symposiums, endoscopy medicine in both countries has developed and matured remarkably, and Korea and Japan have taken a leadership position in this field. In the future, we continuously challenge to advance the symposium further, to hold international sessions, to develop the new KSGE journal Clinical Endoscopy and the JGES journal Digestive Endoscopy through friendly competition. Through those above, we will share useful information with the world and provide leadership in the field of endoscopy medicine.

Safer endoscopic gastric mucosal resection: preoperative proton pump inhibitor administration.

BACKGROUND AND AIM: Control of bleeding is crucial in improving the safety of endoscopic mucosal resection (EMR), and intragastric acidity has a great impact on hemostasis and blood coagulation. Proton pump inhibitors (PPI) are potent suppressors of gastric acid; however, PPI need to be continuously administered orally for several days, and thus initial effects may be insufficient if PPI is only administered immediately after EMR. The aim of this study was to determine whether preoperative administration of PPI prior to EMR can elevate intragastric acidity, facilitate better control of intraoperative bleeding (complete coagulation and hemostasis), prevent postoperative bleeding, and facilitate healing of artificial ulcers. METHODS: A randomized clinical study was conducted in which EMR was performed with or without 1 week of preoperative PPI administration. RESULTS: Artificial ulcers created by EMR healed more rapidly in patients who received preoperative PPI. CONCLUSIONS: The results of the study suggest that preoperative administration of PPI before EMR is useful for controlling and preventing bleeding, and for facilitating the healing of artificial ulcers.

Clinical usefulness of a new infrared videoendoscope system for diagnosis of early stage gastric cancer.

BACKGROUND: Infrared light can penetrate tissue more deeply than visible light. Therefore, an infrared video endoscope may be useful for assessment of gastric submucosal vessels. However, the resolution of currently available infrared video endoscope systems has been unsatisfactory. A new infrared video endoscope system was developed and its clinical utility assessed for diagnosis of early stage gastric cancer. METHODS: Twenty-five patients with early stage gastric cancer and 8 with gastric adenoma underwent endoscopy with the infrared video endoscope system after intravenous injection of indocyanine green. RESULT: Indocyanine green pooling did not appear in adenomas and some intramucosal gastric cancers, whereas it was noted in all submucosally invasive gastric cancers. Tumors not exhibiting indocyanine green pooling were intramucosal, well-differentiated adenocarcinomas of low height (flat-type cancers). CONCLUSION: These results suggest that our new infrared video endoscope provides valuable information about the submucosal aspect of early stage gastric cancer. Infrared video endoscopy may become a powerful technique for determining whether to perform endoscopic mucosal resection.